Temporary Hit Points

Certain effects can give a character temporary hit points. When a character gains temporary hit points, make a note of his or her current hit points before adding the temporary hit points. When the temporary hit points go away, the character's hit points drop to that score. If the character's hit points are already below that score at that time, all the temporary hit points have already been lost, and the character's hit point total does not drop.

When temporary hit points are lost, they can't be restored as real hit points can be, even with medical treatment or magic.